氧化石墨烯改性玄武岩纤维/聚酰亚胺复合材料的制备与摩擦学性能

通过静电自组装法将氧化石墨烯(GO)附着在硅烷偶联剂KH550接枝后的玄武岩纤维表面,并采用热模压工艺制备了GO改性玄武岩纤维/聚酰亚胺复合材料(GBF/PI)。对比研究了聚酰亚胺(PI)、玄武岩纤维/聚酰亚胺(BF/PI)、KH550改性玄武岩纤维/聚酰亚胺(KBF/PI)、GBF/PI复合材料的力学性能和摩擦磨损性能。结果表明,GBF/PI复合材料的维氏硬度、压缩强度和弯曲强度分别为66.5 HV,275.9 MPa和169.8 MPa,较PI试样分别提高约29.2%,45.8%和47.1%,较BF/PI试样分别提高约21.9%,27.0%和28.1%,较KBF/PI试样分别提高约6.9%,20.2%和10.2%。与PI,BF/PI和KBF/PI试样相比,GBF/PI复合材料具有更优的热稳定性,其中GBF/PI的起始分解温度和质量残留率分别为398.4℃和57.70%,明显高于PI树脂的387.5℃和49.36%。摩擦磨损实验结果表明,与GCr15对磨60 min后,GBF/PI的平均摩擦系数为0.617,磨损率为5.22×10^(-6)mm^(3)/(N·m),较PI树脂试样分别低约11.4%和47.2%,较BF/PI试样分别低约7.7%和27.0%,较KBF/PI试样分别低约8.4%和12.0%。GO的引入有利于形成致密均匀的摩擦层,减轻了PI基复合材料摩擦损伤,提高了材料的减磨抗磨性能。

Advances in Researches on Chemical Composition and Functions of Hemerocallis Plants

The genus Hemerocallis is a kind of perennial herbaceous plants of Liliaceae and consists of about 15 species in the world,11 of which can be found in China. Some species of Hemerocallis are widely cultivated for medicinal,edible and ornamental application. Considerable progress had been made in researches on chemical composition and functions of Hemerocallis plants. Previous phytochemical studies on Hemerocallis plants have demonstrated the presence of flavonoids,anthraquinones,alkaloids,terpenoids,triterpenes and triterpenoid saponins,caffeoylquinic acid derivatives,naphthalene glycosides,steroid and steroidal saponins,phenylethanoid glycosides,and lignans. Functional activities of Hemerocallis plants are mainly manifested in sedative hypnotic,antidepressant,antioxidant,anti-tumor,hepatoprotective,antibacterial and insecticidal activities. Chemical composition of Hemerocallis plants is various,and structural type is rich,and has a variety of significant functional activities,so it is worth further study.

GC-MS Analysis on Form and Content of Phytosterol in the Beans from Different Producing Areas

This paper established the GC-MS method to analyze phytosterol in beans and study the content and distribution of phytosterol in green beans,red beans,black beans and soybeans in 5 main producing areas of China(Inner Mongolia,Heilongjiang,Jilin,Hebei,Shandong).This paper used GC-MS method to analyze the content and distribution of campesterol,stigmasterol,sitostanol,brassicasterol,ergosterol,cycloartanol,cycloartenol,2,4-methylenecycloartanol,spinasterol,cholesterol and cholestanol in the beans from different producing areas.Results showed that the content of sterol in green beans was higher than in three other kinds of beans,and the content of sterol in red beans was the lowest.Different producing areas had a significant impact on the content of sterol in beans,and the dominant producing areas included Inner Mongolia and Heilongjiang.The study provided a basis for quality assessment and nutritional evaluation of beans and provided a reference for traceability and variety distinction study of other edible beans.

Transcriptional Profile Alteration of Peripheral Blood in Chronic Hypoxia

Objective Many physiological and pathological conditions,including cyanotic congenital heart diseases(CCHD),are accompanied by chronic hypoxia,which might interfere with the transcription process.However,the transcriptome profile in peripheral blood under hypoxia is still unidentified.The present work aimed to explore the transcriptional profile alteration of peripheral blood in chronic hypoxia.Methods The present study used a chronic hypoxia rat model to simulate the hypoxic state of CCHD patients.Two groups of Sprague-Dawley rats(n=6 per group)were either exposed to hypoxia(10%O2)or normoxia(21%O2)for 3 weeks.Body weight was measured weekly.Peripheral blood was collected and total RNA was extracted for RNA-Seq at the end of the hypoxia treatment.After quality assessment,the library was sequenced by the Illumina Hiseq platform.The differentially expressed genes were screened(false discovery rate<0.05 and fold change>2).The functional annotation analysis and cluster analysis of differentially expressed genes were performed based on the adjusted P-value(padj<0.05).Results Compared with the control group,the body weight of the rats in the hypoxia group was significantly lowered(P<0.01).RNA-Seq results showed that the transcriptome patterns of the two groups had significant differences.In total,872 genes were identified as differentially expressed.Among all,803 genes were downregulated,while only 69 genes were up-regulated in the hypoxia group.The functional enrichment analysis of the 872 genes showed that multiple biological processes involved,such as porphyrin-containing compound metabolic process,hemoglobin complex and oxygen transporter activity.Conclusions Our study demonstrated the transcriptional profile alteration in peripheral blood of chronic hypoxia rat model.This study provided basic data and directions to further understand the physiological and pathological changes in patients with CCHD.

Advances in Researches about Immunoregulatory Functions of Dendrobium Sw.

Based on the researches on immunoregulatory functions of Dendrobium. at home and abroad in recent years,from immune organs,immune cells,and immune molecules,this paper summarized immunoregulatory functions of polysaccharides,glycosides,and alkaloids extracted from Dendrobium. on the body,including reducing the inflammation,inhibiting tumor,and slowing down aging,to provide theoretical references for in-depth researches and development of modern biotechnology for Dendrobium.

Natural long-chain saturated fatty acids doped LNPs enabling spleen selective mRNA translation and potent cancer immunotherapy

Rationally tailored lipid nanoparticles(LNPs)with efficient and tunable delivery of mRNA in vivo are crucial for mRNA vaccines.Selective expression of antigenic protein in lymphoid tissues/organs could improve the immunostimulatory efficacy and safety of LNPs-based mRNA vaccines.Inspired by the metabolic behavior that long-chain saturated fatty acids tending to enter lymphoid tissue rather than the liver,we developed fatty acid-doped LNPs capable of mediating differential protein expressions in the liver and spleen when administered intravenously.When the molar ratio of saturated fatty acid located 60%–70%,the doped LNPs achieved the spleen selective mRNA translation.The mechanism could be attributed to the different cellular uptake behaviors of saturated fatty acids in hepatocytes.Immunization with a model antigen(ovalbumin)mRNA-loaded spleen selective LNPs,we observed enhanced antigen-specific T cell immune responses,and potent immunotherapeutic and immunoprophylactic efficacy in the mouse lymphoma model.Our natural long-chain saturated fatty acids metabolic characteristics-inspired design of LNPs for spleen-selective mRNA vaccines delivery will provide references for designing mRNA vaccines with high efficacy and safety for tumor immunotherapy.

Improving IEC thermal model for oil natural air natural transformers using optimised parameters based on dynamic simulation

Accurate assessment of hot-spot temperature is essential for the safe operation of power transformers.Existing dynamic thermal models cannot estimate hot-spot temperature accurately since some input parameters are roughly determined by transformer capacity and cooling mode while ignoring the effect of winding structure,tank dimensions,and material physical properties.To improve the accuracy of temperature assessment,empirical parameters of the IEC thermal model including thermal constants,winding and oil exponents are optimised with the help of numerical simulation in this article.Based on energy conservation and heat transfer theory,a computational fluid dynamic(CFD)model of a transformer in oil natural air natural(ONAN)cooling mode is established.This CFD model simulates the entity's structure,sizes,and multi-stage heat dissipation processes realistically,so it can more precisely calculate the dynamic hot-spot temperature.According to the simulated temperature curves at different operating conditions,the thermal constants and oil exponent are estimated using non-linear regression,and the winding exponent is optimised using linear regression.A case study is conducted on an ONAN transformer.It shows the improved IEC model with optimised parameters can more accurately evaluate hot-spot temperature,and the absolute error is decreased by 2.4 K(38.7%)compared with traditional thermal models.

国家自然科学基金经费管理改革实践与思考

科研经费作为科研活动的基础保障,其应用效能直接影响科技创新成效。在国家科研经费管理“放管服”改革背景下,科学基金项目经费管理持续优化,通过更加符合科研规律的经费管理政策引导,有效释放科技创新动能,激发创新活力。文章通过梳理近年来国家自然科学基金经费管理改革举措,分析经费管理改革成效,结合国家自然科学基金经费使用和管理实际,从加强经费政策宣贯力度、制定有针对性的管理办法、强化经费信息化管理、全面落实科研财务助理制度等四个方面提出优化建议,将科研经费“放管服”改革的各项政策落细、落准、落稳,从而有效提高科学基金项目经费使用效益。

靶向CCL21/CCR7轴治疗肿瘤转移的研究进展

转移是肿瘤患者死亡最常见的原因,而淋巴转移是大多数肿瘤转移的主要途径之一。近年来,CC趋化因子配体21(CC chemokine ligand 21,CCL21)及其受体CC趋化因子受体7型(CC chemokine receptor type 7,CCR7)在淋巴转移中的作用逐渐受到关注。CCL21主要由淋巴内皮细胞产生,其与树突状细胞(Dendritic cells,DCs)和T细胞等表面CCR7的相互作用是免疫细胞淋巴迁移及淋巴结归巢的主要决定因素。然而,表达CCR7的肿瘤细胞也可以利用类似的机制进入淋巴管进行淋巴转移。如何靶向CCL21/CCR7轴,既能抑制淋巴转移,又不影响抗肿瘤免疫反应已成为肿瘤免疫治疗研究的重要议题。文中将对CCL21/CCR7轴在淋巴转移中的作用及其作为靶点治疗肿瘤转移的临床前和临床试验研究进行综述,为靶向CCL21/CCR7信号轴治疗肿瘤转移的相关研究提供参考。

A high-resolution cell atlas of the domestic pig lung and an online platform for exploring lung single-cell data

The genetically engineered pig is regarded as an optimal source of organ transplantation for humans and an excellent model for human disease research,given its comparable physiology to human beings.A myriad of single-cell RNA sequencing(sc RNA-seq)data on humans has been reported,but such data on pigs are scarce.Here,we apply sc RNA-seq technology to study the cellular heterogeneity of 3-month-old pig lungs,generating the single-cell atlas of 13,580 cells covering 16 major cell types.Based on these data,we systematically characterize the similarities and differences in the cellular cross-talk and expression patterns of respiratory virus receptors in each cell type of pig lungs compared with human lungs.Furthermore,we analyze pig lung xenotransplantation barriers and reported the cell-type expression patterns of 10 genes associated with pig-to-human immunobiological incompatibility and coagulation dysregulation.We also investigate the conserved transcription factors(TFs)and their candidate target genes and constructed five conserved TF regulatory networks in the main cell types shared by pig and human lungs.Finally,we present a comprehensive and openly accessible online platform,Scdb Lung.Our sc RNA-seq atlas of the domestic pig lung and Scdb Lung database can guide pig lung research and clinical applicability.

Novel phenyl-urea derivatives as dual-target ligands that can activate both GK and PPARγ

A series of novel phenyl-urea derivatives which can simultaneously activate gluco kinase(GK)and peroxisome proliferator-activated receptorγ(PPARγ)was designed and prepared,and their activation of GK and PPARγ was evaluated.The structure--activity relationships of these compounds are also described.Three compounds showed potent ability to activate both GK and PPARγ.The possible binding mode of one of these compounds with GK and PPARγ were predicted by molecular docking simulation.

Poroelastoplastic reservoir modeling by tangent stiffness matrix method

As oil and gas extraction activities move into deeper rock formations,many experimental studies and field investigations indicate rock exhibits a plastic behavior rather than a pure linear elastic behavior,so poroelastoplasticity must be taken into account in the reservoir simulation.Because reservoir rock is a porous material consisting of a compressible solid matrix and number of compressible fluids occupying the pore space,fully coupled modeling is required for reservoir simulation considering solid-fluid interaction,complex stress conditions and nonlinear behaviors.But the computational process could be cumbersome when constant tangent stiffness method is used to address the poroelastoplastic behavior.In this paper,a fully coupled poroelastoplasticity reservoir model based on Drucker-Prager yield criterion is implemented the tangent stiffness method,and the computational efficiency is compared with the constant stiffness method.The accuracy of these two methods is demonstrated in one-dimensional consolidation.In a case study,these two methods are used to analyze the stresses and pore pressure of a reservoir and computing results and running efficiency are compared.Also,the linear elastic and nonlinear solutions are compared in one-dimensional consolidation and reservoir modeling.It shows that the difference between results by constant stiffness method and tangent stiffness method is very small,while the tangent stiffness method shows significantly fewer iteration numbers and shorter running time than the constant stiffness method.